JPS5837089Y2 - Battery consumption indicator - Google Patents

Description

[Detailed description of the invention] This invention is a liquid crystal display panel that uses liquid crystal to display counts, etc., and the battery used there is consumed.
The present invention relates to a battery consumption display device that detects when a voltage drop occurs and displays the status of battery consumption using a part of the liquid crystal panel.

In a field-effect liquid crystal display panel using a nematic liquid crystal layer, the molecular axes of the liquid crystal layer sandwiched between two transparent substrates are oriented in a fixed direction near one of the substrates due to alignment treatment. Then, as it moves away from this substrate, it is continuously twisted little by little, and in the vicinity of other substrates, the molecular axis is forced to be 90° with respect to the above (helical structure).

Therefore, such a liquid crystal normally has optical rotation, and has a property that the optical rotation is lost when a predetermined voltage is applied to the two substrates.

Taking advantage of this property, it is widely used in the display parts of various electronic devices such as small electronic calculators and digital electronic watches.

On the other hand, such a liquid crystal display panel is known in which a specific symbol is turned on or off to notify that the battery is depleted.

Among these methods, a method that lights up a specific symbol when the voltage drops,
Although it is very easy to see and convenient, there is a condition that the lighting time is when the battery voltage drops.

That is, in order to display a specific symbol when the voltage is dropping, it is necessary to raise (prevent it from lowering) the effective voltage, which requires a circuit configuration and has the disadvantage of being extremely complicated.

In addition, although it is simple in terms of circuit configuration to turn on a specific symbol during normal operation and turn it off when the voltage drops, the specific symbol is usually displayed at the same time as a count value is being displayed. This has the drawback that it becomes difficult to see the original display part, and that certain symbols are turned off at almost the same time as the count value, etc., slightly earlier, and there is a high possibility that the operator will overlook it. .

This idea was made to improve the above drawbacks.
A part of the liquid crystal display is used to display a specific symbol by removing the voltage when the battery voltage drops.
The present invention aims to provide a battery consumption display device that clearly indicates that the battery voltage has decreased by displaying this specific symbol.

This invention will be explained in detail below based on the illustrated embodiments.

In Fig. 1, reference numeral 11 is a liquid crystal cell in which a nematic layer in which the alignment direction of the liquid crystal molecular axes is twisted by 90 degrees is arranged between two transparent substrates. It has a first electrode and a second electrode made of a transparent metal film.

One surface of the liquid crystal cell 11 is provided in the horizontal direction (arrow
A polarizing plate 12 having a polarizing axis in the direction) is disposed on the other surface, and a polarizing plate 13 having a polarizing axis (in the direction of the arrow Y) which is 90 degrees different from the polarizing axis of the polarizing plate 12 is disposed on the other surface. On the polarizing plate 12 is a parting plate 1 having a display window 141 in the center.
Further, reflective plates 15 are disposed below the polarizing plate 13, and a liquid crystal panel is constructed by forming a laminated structure of these plates.

Further, the liquid crystal cell 11 is provided with a segment electrode 111 for displaying numerical values, and a rectangular electrode 112 for displaying a specific symbol, for example, B, separated from this segment electrode 111.

Correspondingly, one of the polarizing plates 12 and 13 (polarizing plate 13 in this embodiment) has its polarization axis aligned with respect to the main portion 131 facing the numerical display segment electrode 111. Side portions 132 having polarization axes deviated by 90 degrees (in the same direction as the polarization axis X direction of the polarizing plate 12) are arranged side by side, and are opposed to each other at a predetermined location with a positional relationship that includes the rectangular electrode 112.

The partition plate 14 is provided with a cutout window 142 cut out in the shape of a letter B, facing the rectangular electrode 112.

Then, the electrodes are wired to the liquid crystal panel having the above-described structure to form the liquid crystal display section 16.

Next, the display processing for the liquid crystal display section 16 having the above configuration will be explained with reference to FIGS. 2 and 3.

A numerical display signal is applied to the liquid crystal display section 16 from a central processing section (hereinafter abbreviated as CPU) 17 via a display processing section 18 .

That is, the display processing section 18 decodes the data signal sent from the CPU 17 using a decoder (not shown), sends it to the display buffer 181 shown in FIG. 3 for temporary storage, and also stores this data in the first LCD drive circuit 1
82, and in accordance with the timing signal sent to the liquid crystal drive circuit 182, a predetermined voltage is applied to the numerical display segment electrodes 111 in the liquid crystal display section 16 to display numerical data.

On the other hand, a timing signal generation circuit 19 that supplies various timing signals to the CPU 17, display processing section 18, etc. receives power directly from a power source battery 20.

Further, the output of the power supply battery 20 is applied to the CPU 17 via a switch 21 and also to a voltage detection circuit 22.

As shown in FIG. 3, the voltage detection circuit 22 outputs an output from between the connection points of P-channel and N-channel MO8 type field effect transistors 221 and 222 connected in series to the second liquid crystal drive circuit of the display processing section 18. 183.

The transistors 221 and 222 are alternately turned on by receiving signals at their gates, and the gate signal of the transistor 223 is at a bi level when the transistor 223 is non-conducting, and at a low level when the transistor 223 is conductive.
given by the collector.

When the voltage of the power supply battery 20 is above a certain value, a bias is applied to the base of the transistor 223 to make the transistor 223 conductive, and when the voltage decreases below a certain value, the transistor 223 is made non-conductive. The resistance values of the voltage dividing resistors 224 and 225 are set for the transistor 223 so that the base voltage is lowered to the extent that the voltage is lowered by the voltage.

Further, the elector of the transistor 22 is connected to the power supply battery 20 via a load resistor 226 to form an inverter switch.

In such a configuration, when the voltage of the power supply battery 20 is sufficient to drive the liquid crystal display section 16 with a voltage higher than the threshold voltage of the liquid crystal, the transistor 223 is in a conductive state, and therefore the MO5 field effect transistor 221 is in a conductive state. and 222
The voltage of the gate signal is low level.

Therefore, the field effect transistor 221 is in a conductive state and the other transistor 222 is in a non-conductive state.

Therefore, while a bi-level signal voltage is applied to the second liquid crystal drive circuit 183, the timing signal generation circuit 1
A predetermined voltage is applied to the rectangular electrode 112 of the liquid crystal display section 17 according to a timing signal from 7.

However, the light-directing properties of the liquid crystal driven by the rectangular electrode 112 are lost and the light travels straight, and the directions of the polarization axes of the side portions 132 of the polarizing plates 12 and 13 are parallel to each other. , ordinary numerical display segment electrode 1
Unlike No. 11, the optical opening/closing properties are reversed, so the No. 4
As shown in the figure, B is not displayed.

Further, when the voltage of the power supply battery 20 decreases, the transistor 223 becomes non-conductive below a certain predetermined voltage, and as a result, the gate signals of the transistors 221 and 222 become bi-level.

Therefore, the I transistor 221 becomes non-conductive, the transistor 222 becomes conductive, a low-level signal voltage is applied to the second liquid crystal drive circuit 183, and the predetermined voltage is no longer applied to the rectangular electrode 112. The portion of the liquid crystal that should be driven will have a decorative effect.

Therefore, the fine parts 132 of the polarizing plate 12 and the polarizing plate 13
Since the polarization axes of the rectangular electrodes 112 are parallel to each other, no light is transmitted through the rectangular electrode 112 and the area becomes black.
42, a display of B is displayed as shown in FIG. 4, clearly indicating that the power supply voltage has decreased.

In the above embodiment, the polarizing plate 13 is provided with a small part whose polarization axis differs by 90' from the main part, but this may be provided in the polarizing plate 12. In short, it is used to indicate that the power supply voltage has decreased. The relationship between the polarization axes of the polarizing plates that correspond to the electrodes is
It is sufficient that the polarizing plates are provided in an opposite relationship to the polarizing axes of both polarizing plates provided for the numerical display segment.

Therefore, when the two polarizing plates that sandwich the numerical display area are arranged with their polarization axes parallel to each other, and a transparent numerical display is performed on a black background (not limited to black in the case of color polarizing plates), The polarization axes of the two polarizing plates corresponding to the electrodes for clearly indicating that the battery voltage has decreased are arranged in a perpendicular relationship.

In this way, according to this invention, the relationship between the polarization axes of the polarizing plates placed on both sides of the liquid crystal panel is different from that of the main part (displaying numerical data), and the relationship between the driving voltage and the display By reversing the relationship with the state that is applied to the main part, the effective voltage applied between the electrodes, which clearly indicates that the power supply voltage has decreased due to the decrease in the power supply battery, decreases. It will be displayed in the normal display state of numerical display.

Therefore, unlike conventional displays that are displayed by lighting, there is no need to increase the effective voltage, and the accompanying circuit is unnecessary, indicating that battery depletion has been detected by keeping the voltage above the threshold of the liquid crystal. , which has a great practical effect in that it can be displayed.

[Brief explanation of the drawing]

Fig. 1 is an exploded perspective view of a liquid crystal display device showing an embodiment of this invention, Fig. 2 is an overall circuit configuration diagram for driving the liquid crystal display device, and Fig. 3 is a circuit configuration showing the details of the main parts. FIG. 4 is a time table showing the relationship between the display state of B display, the drop state of the battery voltage that distinguishes the non-display state, and the signal voltage input to the first liquid crystal drive circuit. 11... Liquid crystal cell, 111... Segment electrode for numerical display, 112... Rectangular electrode, 1
2.13...Polarizing plate, 131...Main part, 132...Detail part, 14...Parting plate, 141...Display Window, 142...
Cutout window, 15...Reflector, 183...
...Second liquid crystal drive circuit, 20...Power supply battery.

Claims (1)

[Scope of utility model registration request] In a battery consumption display device capable of detecting a drop in the voltage of a drive battery and displaying its consumption status, for each of the above-mentioned display parts of a liquid crystal cell provided with a numerical display part and a specific symbol display part. A first polarizing plate having different polarizing axes and a second polarizing plate having the same polarizing axis are installed, and the driving for the specific symbol display section is stopped in response to a decrease in the voltage of the battery, thereby displaying the specific symbol. A battery consumption display device, which displays a normal display state on the numerical display section.